A point mutation that occurs when a single nucleotide base is erroneously removed or added within a DNA sequence is known as a frameshift mutation. These mistakes, made by DNA polymerase during the replication process, can be detrimental as they directly impact the amino acids coded for within a DNA sequence.

Frameshift Mutations

DNA sequences are read through codons, or series of three nucleotide bases that code for either an amino acid’s inclusion in the building of a protein or to terminate the protein synthesis process. When a nucleotide base is mistakenly added or deleted to a DNA sequence, it impacts every subsequent codon in the sequence because it shifts the entire queue either forward or backward by one nucleotide base. The damage of these frameshift mutations can be illustrated a simple sentence using three-letter words, such as “the dog and cat sat.” If the letter “a” is erroneously inserted between the “t” and “h” of “the,” the sentence transforms into: “tah edo gan dca tsa t.” The result is a sentence that is not legible. The same result occurs in DNA sequences, as most frameshift mutations result in a illegible codon sequence that produces unusable proteins.